Beyond the sandy beaches and shimmering lagoons of the Cook Islands, there is a jungle war being fought.

The location is Atiu, the third-largest of the Cooks' 15 islands. Its original name is Enuamanu – Island of the Birds. But the island's rare and endangered winged natives are under threat from an avian invader - the common or Indian myna.

This aggressive bird is listed in the world's top 100 most invasive species and is one of the greatest threats to native birds in Australia, stealing their territory, nesting sites and food.

It is a prolific breeder and a cunning foe, as any backyard gardener trying to protect a fruit crop will know.

But after a five-year battle, the people of Atiu are hopeful that by September this year, their island will become the first in the South Pacific to be free of the myna.

"When we first started off we estimated there were 12,000 to 13,000 myna birds. Now there are less than 100," said George Mateariki.

Birdman George, as he is widely known, leads the ground war against the common myna. The bird was introduced to the island in the early 1900s to control the Coconut Stick-Insect but soon became a pest itself.

"We're not the only people now recognising it's a pest," said Mr Mateariki.

"Samoa, Fiji, Tonga all over the Pacific, the South Pacific, they're trying to control it. We're the first lot in the South Pacific to try to eradicate it."

'No-one wants to do my job': George

Atiu's offensive began with poisoning and shooting. A $1 bounty for a dead bird was boosted to $2. Before long, mynas were dropping from the trees.

But as the myna population has declined, it has become harder to spot the enemy, let alone catch and kill it.

Now George traverses the island's 27 square kilometres every day to check and set cage traps. It is no mean feat. Atiu's central plateau is ringed by a raised, fossilised coral reef, with its caves, crevices and sharp pinnacles covered in dense rainforest.

When he is not hunting mynas or running his farm, he is out with tourists pointing out the birds which gave his island its original name.

"The native birds are not shy anymore. They are friendly to the people. The numbers of doves, pigeons [and other native species] have improved a lot," he said.

"We can now pick ripe fruit off the trees," says Roger Malcolm, an Atiu resident who is part of the eradication project.

On my family's bird tour with George, he chops down a big bunch of bananas and points out that it has not been ravaged by hungry mynas.

George says the banana plantations are now a favourite feeding ground for the Rimatara lorikeet, and the native chattering kingfisher is eating the coconut stick-insects, which the mynas were introduced to control.

The Rarotongan flycatcher, back from the brink of extinction, is also flourishing on Atiu.

"Everyone's happy," says Birdman George.

But not as happy as they will be when the last common myna is killed.

"We're going to have a big party down here, that's for sure," he laughs.